EP2555888B1 - Tool unit of a rotary kneading machine - Google Patents

Description

The invention relates to a tool unit of a rotary swaging machine for forming preferably rod-shaped or tubular workpieces, with a plurality of arranged around a working axis forming tools which are driven by a tool drive radially to the working axis with a lifting movement and adjusting means by which stroke positions of the forming tools are adjustable in that the forming tools abut one another in a closed state of the forming tools with a closing pressure dependent on the set stroke positions.

Such tool units have long been used in practice for forming rod-shaped or tubular workpieces, in which a defined workpiece longitudinal section is usually reduced in its cross-section.

For this purpose, the tool units basically have at least two forming tools which are to be machined

Workpiece longitudinal section can completely or partially enclose and at the same time for forming the workpiece with a high-frequency, oscillating, movement against each other radially to the workpiece longitudinal section to be moved and thereby exert high radial compressive forces on this. During the forming process, in addition, a rotational relative movement between the workpiece and the Umformknetwerkzeugen is generated, so that the workpiece longitudinal portion is uniformly pressurized over its entire circumference by the Umformknetwerkzeugen.

In rotary swaging, a distinction is essentially made between a so-called feed and a single-jet kneading method, the kneading method used being determined by the workpiece geometry to be produced.

The feed process is characterized in this respect by constantly set stroke positions of the forming tools, i. with respect to the working axis of the tool units during machining constant radial Hubendlagen the forming tools.

In Einstechrundkneten contrast, the stroke positions of the forming tools by a controlled, the actual radial oscillation of the forming tools superimposed, radial opening or closing of the tools changed.

The result of the forming process depends fundamentally on correctly set stroke positions of the forming tools. When (NC-controlled) Einstechrundkneten example those stroke positions of the forming tools, in which the forming tools in a closed state of the forming tools, the so-called closing point abut each other with a dependent of the set stroke positions closing pressure, used as a reference value for the control of the workpiece forming processes.

In practice, in order to set the closing point, the lifting positions of the forming tools are adjusted stepwise in the direction of the working axis of the tool unit (so-called jogging operation) until the lifting positions of the forming tools are set in such a way that an operator is unable to move due to the for the manual driving of the forming tools required force that assumes a correct, ie a desired closing point for a subsequent workpiece forming process is set.

This procedure entails the risk of setting the closing point with a too high closing pressure, so that possibly damage to the machine tool may occur during operation of the tool unit.

A tool unit of a rotary swaging machine and a method for setting such a tool unit, in the case of which the resulting at the set stroke positions of the forming tools closing pressure can be checked, are known from DE 199 55 321 A1 , This document discloses a rotary swaging machine with a hammer shaft on which a plurality of machining tools in the radial direction of a continuous axis of a workpiece to be machined are movably guided. For workpiece machining, the processing tools are acted upon at their remote from the workpiece side intermittently by plunger. To drive the plunger are circulating within an outer ring Rollers are provided, which move over the heads of the plunger away while driving the plunger in the direction of the workpiece to be machined. Between each of the plungers and the processing tool associated therewith, a piston-cylinder arrangement is provided with a compression space whose internal pressure is measured.

Starting from the prior art according to DE 199 55 321 A1 The present invention has set itself the goal of allowing a measurement of the closing pressure on tool units of the type mentioned with structurally particularly simple means.

Related to the device, this object is achieved by the tool unit according to claim 1, related to the method by the method according to claim 11.

According to the invention, a measuring device for measuring a parameter is provided in the tool unit mentioned above, by means of which a drive torque for driving the forming tools can be determined. On the one hand, this makes possible a construction of the measuring device which is particularly simple in terms of construction, since no plurality of measuring transducers assigned to the respective forming tools are required. In addition, the determination of the drive torque allows reliable (summed over the forming tools) checking the closing pressure of the forming tools, since this results from the introduced into the forming tools driving torque of the tool drive and is proportional to this. In addition, by the determination of the drive torque in particular overloads of the drive train can be prevented.

In general, the stroke positions of the forming tools of the tool unit can be adjusted in a simple and reproducible manner by means of a measuring device for checking the closing pressure of forming tools in such a way that a defined closing pressure is given or maintained in the closing point of the forming tools. As a result, the risk of overloading the components of the tool unit and thus their damage is minimized. In addition, the adjustment of the tool unit is facilitated and can also be performed by a less experienced operator. In addition, due to the objectified and reproducible setting of the closing point lower tolerance variations of the forming products can be realized, which is particularly in the production of high-precision components with tight tolerances advantage.

Advantageous embodiments of the invention according to claim 1 emerge from the features of the dependent claims 2 to 10 and an advantageous embodiment of the invention according to claim 11 results from the features of the dependent claim 12th

A particularly preferred embodiment of the invention is characterized in that a control unit for closing pressure control is provided, wherein the measured parameter for checking the closing pressure by the control unit, in particular with respect to a Sollbereichs- or setpoint specification, is processable.

The associated advantage is essentially that the adjustment of the tool unit is facilitated. In the simplest case, measured values of the measuring device can thus be provided in such a way that they are accessible to the operator, for example, by a display unit can be made. In this case, a check of the closing pressure by the user, for example by means of corresponding tables, by means of which the operator is able to assign a corresponding closing pressure to the measured value, is furthermore required. In the advantageous case of reference to a desired range or setpoint specification, information based on an evaluation of the measured values of the parameter can be made available by the control unit. These can, for example, inform about a too low, a correct or too high closing pressure setting and made accessible to the operator via an audible or visual display. As a result, the setting of the tool unit is greatly facilitated overall and increases the ease of use. At the same time, the risk of incorrect settings and associated damage to the tool unit is minimized further.

The tool unit preferably has an operating mode which can be selected via the control unit for checking the closing pressure. This offers the advantage that the risk of overloading the tool unit and the associated damage is reduced. In particular, the forming tools can either be selectively moved to the closing point and held in this. However, the forming tools are preferably driven with a small number of strokes sufficient for a reliable measurement of the parameter, whereby dynamic effects occurring during the drive of the forming tools can also be taken into account, at least partially.

The drive can be provided according to the invention for generating a relative rotational movement of a tool holder and a tool holder surrounding the outer ring, resulting in a particularly robust and in operation against disturbances little vulnerable type of tool unit results.

From a constructional point of view, it has proved to be advantageous that the measuring device is provided for measuring the current consumption of the tool drive when driving the forming tools. The take-up current of the tool drive is on the one hand closely with the (electric) power consumption of the tool drive, on the other hand with the drive torque applied by the tool drive correlates and therefore allows a simple and reliable determination of these key figures. By means of these ratios, the derived from the drive torque of the tool drive closing pressure of the forming tools can be determined without much effort. Such a measuring device is still largely insensitive to the vibrations occurring during operation of the tool unit and offer a cost advantage due to their free availability on the market, spielspielsweise compared to other more sophisticated means for determining the drive torque.

In the case of the indirect closing pressure determination via the power consumption of the tool unit, the measuring device preferably additionally detects an operating voltage respectively applied to the tool drive, by means of which the power consumption can be determined by calculation.

The closing pressure can preferably be determined by the control unit on the basis of a characteristic curve, preferably defined in the control unit, for the parameter or a characteristic number determined by the parameter and the closing pressure. The characteristic curve describes the relationship between the measured parameter or a characteristic number determined by means of the parameter and the closing pressure of the forming tools and can be stored in tabular form or in the form of a mathematical formula in the control unit.

According to one embodiment of the invention, the adjusting means are formed as a plurality of, preferably between the forming tools and these respective associated Hämmerstößeln out, adjusting wedges, which are arranged parallel to the working axis, said Adjusting wedges for adjusting the stroke position of the forming tools in the direction of the working axis relative to the forming tools are longitudinally displaceable. As a result, a particularly robust and insensitive to interference influences Hublagenverstellung, even during the forming process, allows.

The adjusting means are preferably jointly adjustable according to the invention and for this purpose in particular with an adjusting means, for example a synchronous shaft, connected.

The risk of an excessively high closing pressure setting is further minimized by the fact that the adjusting means are controllable by means of the control unit as a function of the closing pressure.

According to a development of the invention, the stroke positions of the forming tools or a setting position of the feed means correlating with the stroke position can be used as a reference value for the control of the tool unit in a subsequent workpiece forming process, since all radial dimensions of the product to be manufactured by the workpiece forming process are defined based on the closing point. The respective reference value is advantageously automatically transferable to a machine control of the rotary swaging machine.

Preferably, the measuring device and / or the control device is an integral part of a machine control of a rotary kneading unit or is covered by it.

Depending on the requirements imposed on it, the tool unit may also preferably be designed as an external, internal or double rotor, in particular as a counter-rotor, according to the invention.

Fig. 1

eine perspektivische Ansicht einer Werkzeugeinheit einer ausschnittsweise dargestellten Rundknetmaschine;

Fig. 2

eine schematisierte Vorderansicht eines Knetwerks einer der Fig. 1 entsprechenden Werkzeugeinheit mit vier Umformwerkzeugen, die sich in geschlossener Stellung befinden; und

Fig. 3

eine schematisierte Schnittdarstellung des in der Fig. 2 gezeigten Knetwerks mit einem zwischen den Umformwerkzeugen angeordneten Werkstück.

The invention will be explained in more detail with reference to an embodiment shown in the drawing. In the drawing show:

Fig. 1

a perspective view of a tool unit of a partially illustrated rotary swaging machine;

Fig. 2

a schematic front view of a kneader one of Fig. 1 corresponding tool unit with four forming tools, which are in the closed position; and

Fig. 3

a schematic sectional view of the in the Fig. 2 shown kneading with a arranged between the forming tools workpiece.

In the Fig. 1 is a total of 10 designated tool unit of only partially reproduced rotary swaging machine 12 for forming preferably rod-shaped or tubular workpieces shown. The tool unit 10 has a housing 14 with a feed opening 16 arranged on the front side for feeding the workpieces to be reshaped along a working axis denoted by 18. The housing 14 surrounds a in the Fig. 2 closer reproduced kneading 20, which has a plurality of forming tools 22 which are arranged around the working axis 18. The forming tools 22 are together with hammer rams 24 in radial recesses 26 of a trained as a kneading head tool holder 28 and guided by a tool drive 30 (FIGS. Fig. 1 ) can be driven radially to the working axis 18 with a lifting movement.

A tool holder 28 concentrically arranged outer ring 32 surrounds the tool holder 28 and thus forms with the tool holder 28 an annular space 34, in which formed as rollers pressure members 36 are arranged.

The tool unit 10 is formed in the embodiment shown here as an external rotor, ie, the outer ring 32 is by the tool drive 30 (FIG. Fig. 1 ) with respect to the tool holder 28 circumferentially drivable. The hammer plunger 24 protrude into an orbit of the co-moving by the rotation of the outer ring 32 pressure members 36 and are in radial alignment with a respective pressure member 36, as shown in the Fig. 2 is shown, moved by this radially inwardly in the direction of the working axis 18 and press the forming tools 22 intermittently radially in the direction of the working axis 18. The forming tools 22 practice thereby on a along the working axis 18 between the forming tools 22 introduced workpiece a mutually facing Pressure pulse through which the workpiece is formed. The number of strokes of the driven forming tools 22 may be several thousand strokes per minute during the forming process.

The tool unit 10 has for adjusting the stroke position of the forming tools 22 in the radial direction relative to the working axis 18 a plurality of setting means 38 formed as adjusting wedges on. By means of the adjusting means 38, the stroke positions of the forming tools 22 are adjustable so that the forming tools 22 in a closed state of the forming tools 22, as this in the Fig. 2 is shown, the closing point explained above, abut each other with a dependent of the set stroke position closing pressure.

Like from the Fig. 2 It can be seen that the forming tools are not in the closing point with each other with their workpiece-side work surfaces, but with their mutually facing side surfaces, the so-called roofs, on.

The adjusting means 38 are in the embodiment shown here parallel to the working axis 18 in the direction of the highly schematic representation in the Fig. 3 Arranged with 39 directional arrows longitudinally displaceable. The adjusting means are, as this particular from the Fig. 3 shows, arranged in a conventional manner in each case between one of the forming tools 22 and the forming tool 22 each associated hammer plunger 24 and guided in axial recesses of the tool holder 28 (not shown). The adjusting means 38 are also arranged in each case with its insertion opening 16 facing away from the end of a not shown in detail in the drawing synchronous shaft and axially displaceable together by this.

The tool unit 10 according to the invention further comprises a measuring device 40, which for determining a respective electrical power consumption of the tool drive 30, a respective receiving current of the tool drive 30 and one on the Tool drive 30 applied operating voltage when driving the outer ring 32 and the forming tools 22 detected.

The power consumption of the tool drive 30 is proportional to the closing pressure of the forming tools 22 derived from a drive torque of the tool drive, so that the closing pressure resulting at the set stroke positions of the forming tools 22 in the closing point of the forming tools 22 by a in the Fig. 1 shown control unit 42 can be determined or determined by means of the specific power consumption of the tool drive.

The control unit 42 checks the closing pressure in relation to a presettable via the control unit 42 closing pressure target value based on a respective defined in the control unit 42 characteristic curve, from which the relationship between the power consumption of the tool drive 30 and the closing pressure emerges. In the control unit 22 respective characteristic curves are deposited in this respect for different forming tools 22 or combinations of hammer rams 24 and forming tools 22.

The adjustment means 38 ( Fig. 2 ) are controllable with respect to their displacement or their displacement position by means of the control unit 42 in dependence on the setpoint specification.

To check the closing pressure, the tool unit 10 additionally has an operating mode of the tool device 10 that can be selected via the control unit 42 for checking the closing pressure. In this mode of operation, the rotary tools 22 are opposite one the stroke numbers used for the forming processes lower stroke number drivable.

The stroke positions of the forming tools 22 set in response to the set point specification of the closing pressure, i. the axial position of the synchronous shaft correlating with the adjusted stroke position can be automatically transferred by the control unit 42 to a machine controller 44 of the rotary kneader 12 as a reference value for the control of the subsequent workpiece forming processes, on the basis of which radial dimensions of a formed product to be manufactured can be defined.

In the context of the invention, the tool unit 10 can also be designed as an internal or double rotor, in particular as a counter rotor, depending on the requirements imposed on it.

Hereinafter, the check of the closing pressure of the forming tools 22 in response to the adjustment of the stroke positions of the forming tools 22 during the establishment of a tool unit 10 after the Fig. 1 to 3 briefly sketched.

After upgrading the tool unit 10 with the forming tools 22 required for the respective forming process, a desired value of the closing pressure of the forming tools 22 is set via the control unit 42 at the closing point of the forming tools 22 or a parameter correlating with the closing pressure.

In a second step, an operating mode of the tool unit provided for closing pressure control is used to check the closing pressure 10 via the control unit 42 on or selected, whereby the outer ring 32 is placed over the tool drive 30 for checking the closing pressure in a relative (slow) rotational movement, in which the determination of the power consumption of the tool drive, ie the detection of power consumption and the applied operating voltage can occur and possible risks of overloading of the tool unit 10 are minimized. The stroke position of the forming tools 22 is not delivered at this time in the direction of the working axis 18, ie the forming tools 22 are not yet in a closed state at this time.

The adjusting means 38 are now controlled by the control unit 44 via the synchronous shaft (not shown) such that the adjusting means 38 are adjusted continuously or stepwise by means of the synchronous shaft for adjusting the stroke position of the forming tools 22 in the direction of the working axis 18. In the present case, the adjusting means 38 are for this purpose in the direction of the insertion opening 16 of the housing 14 (FIG. Fig. 1 ) of the tool unit 10, wherein the receiving current and the operating voltage of the tool drive 30 measured during simultaneous rotation of the outer ring 32 by means of the measuring device 40 and from these parameters, the power consumption of the tool drive 30 is determined.

To check the closing pressure of the forming tools 22, the power consumption of the tool drive determined from the pickup current and the operating voltage of the tool drive 30 is compared with the closing pressure setpoint based on the characteristic curve defined in the control unit 42. Upon reaching a correlated with the predetermined closing pressure setpoint power consumption of Tool drive 30, the adjustment of the adjusting means 38 in the closing point of the forming tools and thus the adjustment of the stroke positions of the forming tools 22 is completed.

The setting position of the adjusting means 38 or the synchronizing shaft in the stroke positions of the forming tools thus defined are automatically transferred as a reference value for the control of subsequent workpiece forming processes to the machine controller 44 of the rotary swaging machine 12.

Claims (12)

1. Tool unit of a rotary swaging machine (12) for forming preferably rod-like or tubular workpieces, having a plurality of forming tools which are arranged around an operating axis (18) and which can be driven by means of a tool drive (30) radially with respect to the operating axis (18) with a stroke movement and having adjustment means (38), by means of which stroke positions of the forming tools (22) can be adjusted in such a manner that the forming tools (22) in a closed state of the forming tools (22) are in mutual abutment with a closure pressure which is dependent on the adjusted stroke positions, characterised in that the closure pressure produced in the adjusted stroke positions of the forming tools (22) can be verified by a measuring device (40) being provided for measuring a parameter, by means of which a drive torque for driving the forming tools (22) can be determined.
2. Tool unit according to claim 1, characterised in that a control unit (42) is provided for controlling the closure pressure, the measured parameter for verifying the closure pressure being able to be processed by the control unit (42), in particular with respect to a desired range or desired value provision.
3. Tool unit according to either claim 1 or claim 2, characterised in that an operating mode of the tool unit (10) is provided to verify the closure pressure, which mode can be selected by means of a control unit (42) for controlling the closure pressure.
4. Tool unit according to any one of the preceding claims, characterised in that the tool drive (30) is provided in order to produce a relative rotational movement of a tool retention member (28) and an outer ring (32) which surrounds the tool retention member (28).
5. Tool unit according to any one of the preceding claims, characterised in that the measuring device (40) measures as a parameter an electrical current consumption of the tool drive (30) when the forming tools (22) are driven.
6. Tool unit according to any one of claims 2 to 5, characterised in that the closure pressure can be determined by means of the control unit (42) with reference to a characteristic line preferably defined in the control unit (42) for the measured parameter or a characteristic number of the tool drive and the closure pressure, which characteristic number is determined from the parameter.
7. Tool unit according to any one of the preceding claims, characterised in that the adjustment means (38) are constructed as a plurality of adjustment wedges which are preferably guided between the forming tools (22) and hammer tappets (24) associated therewith, and which are arranged parallel with the operating axis (18), the adjustment wedges being able to be longitudinally displaced in the direction towards the operating axis (18) with respect to the forming tools (22) in order to adjust the stroke positions of the forming tools (22).
8. Tool unit according to any one of claims 2 to 7, characterised in that the adjustment means (38) can be controlled by means of the control unit (42) depending on the closure pressure.
9. Tool unit according to any one of the preceding claims, characterised in that the stroke position of the forming tools (22) or an adjustment position of the adjustment means (38) correlating to the stroke position can be used as a reference value for controlling workpiece forming processes.
10. Tool unit according to any one of the preceding claims, characterised in that the tool unit (10) is constructed as an outer, inner or dual rotor, in particular as a counter-rotor.
11. Method for adjusting a tool unit according to any one of the preceding claims, wherein a closure pressure which results from the adjusted stroke position of the forming tools (10) in the closure location thereof is verified by means of a measuring device (40) by the measuring device (40) measuring a parameter by means of which a drive torque for driving the forming tools (22) can be determined.
12. Method according to claim 11, characterised in that the closure pressure is verified whilst the forming tools are driven and the stroke positions of the forming tools are simultaneously adjusted.

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